/* =========================================================
   全局变量（主题色 / 文本色 / 背景色）
========================================================= */
:root{
  --main:#2563eb;      /* 主色（蓝） */
  --sub:#7c3aed;       /* 辅助色（紫） */
  --bg:#f8fafc;        /* 页面背景色 */
  --text:#0f172a;      /* 主文本颜色 */
  --muted:#64748b;     /* 次级/说明文字颜色 */
}

/* =========================================================
   RESET & 基础设置
========================================================= */
*{
  margin:0;
  padding:0;
  box-sizing:border-box;
}

html,body{
  height:100%;
  overflow-x:hidden;   /* 防止横向滚动条 */
  overflow-y:auto;     /* 确保纵向滚动条正常 */
}

body{
  min-height:100vh;
  display:flex;
  flex-direction:column;

  font-family:Segoe UI,Roboto,sans-serif;
  background:var(--bg);
  color:var(--text);
  line-height:1.7;
  padding-bottom:0;    /* 去掉不必要的底部空白 */
}

/* =========================================================
   顶部导航栏（NAV）
========================================================= */
nav{
  position:fixed;
  top:0;
  left:0;
  width:100%;
  height:64px;
  z-index:1000;

  display:grid;
  grid-template-columns:auto 1fr auto;
  align-items:center;

  padding:0 24px;
  background:#ffffffee;
  backdrop-filter:blur(10px);
  border-bottom:1px solid #e5e7eb;
}

/* ===== 导航链接高级交互 ===== */
.nav-link{
  position:relative;
  padding:6px 2px;

  font-size:1em;
  font-weight:500;
  color:var(--text);
  text-decoration:none;

  transition:
    color .25s ease,
    transform .25s ease;
}

/* 文字 hover */
.nav-link:hover{
  color:var(--sub);
  transform:translateY(-1px);
}

/* 渐变下划线 */
.nav-link::after{
  content:"";
  position:absolute;
  left:0;
  bottom:-6px;

  width:0;
  height:2px;
  border-radius:999px;

  background:linear-gradient(
    90deg,
    #7c3aed,
    #8b5cf6
  );

  transition:width .3s ease;
}

/* hover 时展开下划线 */
.nav-link:hover::after{
  width:100%;
}

/* Logo */
.logo{
  font-size:1.2em;
  font-weight:700;
  color:var(--main);
}

/* ===== Logo 渐变品牌感 ===== */
.logo-gradient{
  font-size:1.6em;
  font-weight:800;
  letter-spacing:.3px;

  background:linear-gradient(
    135deg,
    #7c3aed,
    #8b5cf6
  );
  -webkit-background-clip:text;
  -webkit-text-fill-color:transparent;

  cursor:pointer;
  transition:transform .25s ease, filter .25s ease;
}

.logo-gradient:hover{
  transform:scale(1.05);
  filter:brightness(1.1);
}

/* 中间导航链接 */
.nav-center{
  display:flex;
  justify-content:center;
  gap:28px;
}

.nav-center a{
  text-decoration:none;
  color:var(--text);
  font-weight:500;
}

/* 右侧功能区（语言/按钮等） */
.nav-right{
  display:flex;
  align-items:center;
  gap:16px;
}

/* =========================================================
   语言切换（LANGUAGE）
========================================================= */
.lang{
  position:relative;
}

.lang-btn{
  cursor:pointer;
}

.lang-menu{
  display:none;
  position:absolute;
  right:0;
  top:28px;

  background:#fff;
  border:1px solid #e5e7eb;
  border-radius:10px;
  overflow:hidden;
}

.lang-menu div{
  padding:10px 16px;
  cursor:pointer;
}

.lang-menu div:hover{
  background:#f1f5f9;
}

/* =========================================================
   页面通用结构（内页：About / Services / Contact）
========================================================= */
.page,
.about-bg{
  min-height:calc(100vh - 64px); /* 保证至少一屏，扣掉导航 */
  display:flex;
  flex:1;
  flex-direction:column;
  justify-content:flex-start;
  padding:120px 8% 80px;
  box-sizing:border-box;  /* 防止溢出 */
  overflow:hidden; /* 防止页面溢出 */
}

/* =========================================================
   首页 HERO
========================================================= */
.hero{
  min-height:calc(100vh - 64px); /* 视口高度 - 导航栏高度 */
  display:flex;
  flex-direction:column;
  justify-content:flex-start;
  align-items:center;
  padding:140px 8% 60px;
  text-align:center;
  background:
    radial-gradient(circle at 20% 20%, #93c5fd55, transparent 45%),
    radial-gradient(circle at 80% 30%, #c4b5fd55, transparent 45%);
  box-sizing:border-box;   /* 确保布局无溢出 */
}

/* ===== 首页标题 ===== */
.hero h1{
  font-size:3em;
  margin-bottom:20px;
  animation:fadeUp .8s ease forwards;
}

/* ===== 首页描述 ===== */
.hero p{
  max-width:800px;
  margin:0 auto 36px; /* 与 services 视觉节奏一致 */
  color:var(--muted);
  animation:fadeUp .8s ease .15s forwards;
}

/* ===== 首页按钮 ===== */
.hero .btn{
  margin-top:40;
}

/* =========================================================
   About / Services 背景与标题
========================================================= */
.about-bg{
  text-align:center;
  background:
    radial-gradient(circle at 15% 20%, #93c5fd55, transparent 45%),
    radial-gradient(circle at 85% 30%, #c4b5fd55, transparent 45%);
}

/* 标题区与卡片区的间距 */
.about-hero{
  margin-bottom:64px;
}

/* About / Services 主标题 */
#aboutTitle,
#servicesTitle{
  position:relative;
  font-size:2.4em;
  margin-bottom:20px;

  opacity:0;
  transform:translateY(20px);
  animation:fadeUp .8s ease forwards;
}

/* 标题下方紫色装饰线 */
#aboutTitle::after,
#servicesTitle::after{
  content:"";
  display:block;
  width:42px;
  height:3px;
  margin:16px auto 0;
  border-radius:999px;
  background:linear-gradient(90deg,#7c3aed,#8b5cf6);
}

/* 标题描述文字 */
#aboutDesc,
#servicesDesc{
  max-width:640px;
  margin:0 auto 72px;

  color:var(--muted);
  line-height:1.85;
  font-size:1.05em;
  letter-spacing:-0.015em;

  opacity:0;
  transform:translateY(20px);
  animation:fadeUp .8s ease .15s forwards;
}

/* =========================================================
   卡片组件（Cards）
========================================================= */
.cards{
  display:grid;
  grid-template-columns:repeat(auto-fit,minmax(240px,1fr));
  gap:28px;
}

.card{
  background:#fff;
  padding:32px;
  border-radius:18px;

  box-shadow:0 10px 30px #00000010;

  opacity:0;
  transform:translateY(40px);
  transition:
    transform .25s ease,
    opacity .6s ease,
    box-shadow .35s ease,
    background .45s ease;
}

/* 滚动显示动画 */
.card.show{
  opacity:1;
  transform:translateY(0);
}

/* Hover 效果 */
.card:hover{
  transform:translateY(-6px);
  box-shadow:0 18px 40px #00000018;
  background:
    radial-gradient(circle at top left,#93c5fd33,transparent 60%),
    #ffffff;
}

/* =========================================================
   通用按钮（Button）
========================================================= */
.btn{
  display:inline-flex;
  align-self:center;
  align-items:center;
  justify-content:center;

  padding:14px 40px;
  border-radius:999px;

  font-size:1em;
  font-weight:600;
  text-decoration:none;
  color:#fff;

  background:linear-gradient(135deg,#7c3aed,#8b5cf6);
  box-shadow:0 8px 25px rgba(124,58,237,.4);

  transition:
    transform .25s ease,
    box-shadow .25s ease,
    filter .25s ease;
}

.btn:hover{
  transform:translateY(-3px);
  box-shadow:0 14px 35px rgba(124,58,237,.5);
  filter:brightness(1.07);
}

/* =========================================================
   联系页（Contact Page）
========================================================= */

/* Contact 页面不垂直居中 */
.contact-page{
  justify-content:flex-start;
  padding-bottom:160px; /* 防止 footer 遮挡 */
}

/* 表单容器 */
.contact-wrap{
  max-width:760px;
  margin:0 auto;
  padding:0 8%;
}

/* 表单卡片 */
.contact-card{
  padding:40px;
  text-align:left;
}

/* 表单结构 */
.contact-form{
  display:flex;
  flex-direction:column;
  gap:20px;
}

/* 两列输入行 */
.contact-form .form-row{
  display:grid;
  grid-template-columns:1fr 1fr;
  gap:16px;
}

/* 输入框样式 */
.contact-form input,
.contact-form textarea{
  width:100%;
  padding:14px 16px;

  font-size:.95em;
  font-family:inherit;

  border-radius:10px;
  border:1px solid #e5e7eb;

  transition:border .25s ease, box-shadow .25s ease;
}

/* 聚焦状态 */
.contact-form input:focus,
.contact-form textarea:focus{
  outline:none;
  border-color:var(--sub);
  box-shadow:0 0 0 3px rgba(124,58,237,.15);
}

/* 文本域 */
.contact-form textarea{
  resize:vertical;
}

/* 发送按钮 */
.contact-form button{
  margin-top:20px;
  align-self:flex-start;
}

/* =========================================================
   页脚（Footer）调整
========================================================= */
footer{
  position:relative;  /* 让页脚不再固定，避免被遮挡 */
  width:100%;
  height:auto; /* 根据内容高度调整 */
  background:#0f172a;
  color:#cbd5f5;
  display:flex;
  align-items:center;
  justify-content:center;
  font-size:.9em;
  padding:20px 0; /* 增加上下内边距，给内容空间 */
}

/* =========================================================
   下拉菜单动画（Mobile）
========================================================= */
@keyframes slideDown {
  from {
    opacity: 0;
    transform: translateY(-10px);
  }
  to {
    opacity: 1;
    transform: translateY(0);
  }
}

.nav-dropdown {
  display: none; /* 默认隐藏下拉菜单 */
  position: absolute;
  top: 64px; /* 距离导航条下方 */
  right: 0;
  background: #fff;
  box-shadow: 0 4px 8px rgba(0, 0, 0, 0.1);
  border-radius: 8px;
  overflow: hidden;
  width: 200px;
  animation: slideDown 0.3s ease-out forwards; /* 增加下拉动画 */
}

/* 当菜单打开时显示动画 */
.nav-mobile.open .nav-dropdown {
  display: block;
}


/* =========================================================
   动画（Animations）
========================================================= */
/* =========================================================
   下拉菜单动画（Mobile）
========================================================= */
@keyframes slideDown {
  from {
    opacity: 0;
    transform: translateY(-10px);
  }
  to {
    opacity: 1;
    transform: translateY(0);
  }
}

.nav-dropdown {
  display: none; /* 默认隐藏下拉菜单 */
  position: absolute;
  top: 64px; /* 距离导航条下方 */
  right: 0;
  background: #fff;
  box-shadow: 0 4px 8px rgba(0, 0, 0, 0.1);
  border-radius: 8px;
  overflow: hidden;
  width: 200px;
  animation: slideDown 0.3s ease-out forwards; /* 增加下拉动画 */
}

/* 当菜单打开时显示动画 */
.nav-mobile.open .nav-dropdown {
  display: block;
}